Symplectoscyphus plectilis (Hickson and Gravely, 1907)

Peña Cantero, A. L., 2002, Species of Symplectoscyphus Marktanner-Turneretscher, 1890 (Cnidaria: Hydrozoa, Sertulariidae) from recent Antarctic expeditions with R. V. Polarstern, with the description of four new species, Journal of Natural History 36, pp. 1509-1568 : 1550-1553

Symplectoscyphus plectilis (Hickson and Gravely, 1907)

(gure 12; table 12)

Sertularella plectilis Hickson and Gravely, 1907: 20 , pl. 3, gure 21; Ritchie, 1913: 10, 30, gures 8, 9, 11; Jäderholm, 1917: 10, pl. 1, gure 8; 1926: 5; Stepan’yants, 1972: 69, gure 14; 1979: 74, pl. 13, gure 4.

Sertularella (Symplectoscyphus) plectilis: Broch, 1948: 5 , 9–13, gure 2f, g.

Symplectoscyphus plectilis: Stechow, 1922: 148 ; 1923: 172; Totton, 1930: 193, gure 41, pl. 2, gures 4, 5; Rees and Thurs eld, 1965: 131; Blanco, 1967b: 77, pl. 5, gures 11–15; 1984: 29–31, gures 58–61 on pls 26, 27; 1992: 149–153, gures 7–10; Vervoort, 1972b: 354, gure 8b, c; 1993: 241; Bouillon, Massin and Kresevic, 1995: 74.

? Symplectoscyphus plectilis: Vervoort, 1972a: 133 , gure 42; Naumov and Stepan’yants, 1972: 34, 42; Millard, 1977: 34, gure 11A–C.

Sertularella glacialis: VanhöVen, 1910: 325 , gure 40a–c.

Symplectoscyphus naumovi: Blanco and Bellusci de Miralles, 1972: 19 , gure 33.

Symplectoscyphus sp. 4 Peña Cantero and Garcóa Carrascosa, 1995: 92, gure 40f–h.

Not Symplectoscyphus plectilis: Blanco, 1984: 29–31 , gures 58– 61 5 S . naumovi Blanco, 1969.

Material examined. Type material, loaned from The Natural History Museum, London, No. 1907.8.20.35.

Polarstern material: ANT VIII-5 Stn 16-492, a mass of stems ca 10 mm diameter and numerous stems up to 25 mm high, with gonothecae, on Halecium sp. (RMNH- Coel. 29 197, slide 4842).

Description. Delicate and monosiphonic stems up to 25 mm high. Branching frequent. Some branches forming stolons and anastomosing amongst them.

Hydrothecal internodes long and thin, usually longer than hydrothecae. Hydrothecae situated at distal part of internode and alternately arranged in one plane (gure 12A–F).

Hydrothecae almost cylindrical, slightly abcaudally directed (gure 12A–F). Adcauline hydrothecal wall free for approximately two-thirds its length. Free part of adcauline hydrothecal wall convex. Abcauline hydrothecal wall slightly concave. Cusps of hydrothecal aperture sharp and separated by deep embayments (gure 12A–F). Hydrothecae extremely delicate; frequently collapsed.

2014

February

13

38

:

23

at

]

Bath of

University

[

by

Downloaded

Gonothecae fusiform, with waved walls and a short distal neck bearing the aperture (gure 12G, H).

Remarks. Naumov and Stepan’yants (1972) assigned to S. plectilis material that according to those authors has ‘a structure typical of this species’. However, since they give neither gure nor measurements it is not possible to ascertain if they are actually conspeci c.

Millard (1977) identi ed as S. plectilis a form that has hydrothecae distinctly

Downloaded by [University of Bath] at 23:38 13 February 2014 Table 12. Measurements of Symplectoscyphus plectilis (Hickson and Gravely, 1907) (in m m).

†Own measurements.

‡Taken from the gures.

§Immature.

smaller than those described by other authors. Moreover, the material was infertile, so that it is not possible to establish with certainty if it belongs to Hickson and Gravely’s species. Until Millard’s material is re-examined we will doubtfully keep it in S. plectilis .

Vervoort (1972a) assigned to S. plectilis a fragment 8 mm long, provided with hydrothecae having a diVerent shape than those typically referred to S. plectilis . In Vervoort’s material the hydrotheca has a marked in exion point where the hydrotheca becomes free, being distinctly directed abcaudally, whereas in S. plectilis there is a continuity between the free and adnate parts of the adcauline wall. Moreover, the hydrothecal diameter clearly decreases towards the aperture in Vervoort’s material, whereas in S. plectilis it is almost constant throughout the hydrotheca. We have doubts about the proper assignation of that material.

In Symplectoscyphus plectilis the hydrothecal walls are extremely thin and are frequently collapsed ( Ritchie, 1913 and others).

2014 Ecology and distribution. Symplectoscyphus plectilis has been found at depths

February

from debris bottoms 7 ((Totton Vervoort ( Totton, 1930,, 1930 1972), rocky; b Broch) to bottoms 457, 1948 m () Totton (, Stepan’yants bottoms, 1930 of) mud,. 1979 It has with), been and undecomposed bottoms collected of on boulders muddy animal, stones and sand, stones and mud, and stones (Naumov and Stepan’yants, 1972).

13 Our material was collected at a depth of 250 m on a bottom composed of fragments

38

: of bryozoans.

23 Symplectoscyphus plectilis was observed epibiotic on hydroids [ Oswaldella

at

] antarctica (Jäderholm 1904) , Schizotricha unifurcata Allman, 1883 ], sponges and

Bath bryozoans by Naumov and Stepan’yants (1972) and hydroids by Stepan’yants (1979). We also found it on hydroids ( Halecium sp. ). Ritchie (1913) found it

of

with gonothecae from June to August, Totton (1930) in

January and February

University and collected Symplectoscyphus Stepan’yants in February (1979. plectilis ) from has January a circum-Antarctic to December. The distribution Polarstern (Stepan’yants material was,

[1979), being known from both East and West Antarctica. In the former, it has been

by

reported from McMurdo Sound ( Ritchie, 1913; Totton, 1930), Cape Royds (Ritchie,

Downloaded (and

1913 recorded Naumov in) and the from and Discovery Sea Stepan’yants of South Friendship Island Georgia, (1972 Jäderholm (Stepan’yants (Jäderholm), in the, 1926,, Davis 1917 1979), in)),. Sea In the at West (64 Stepan’yants Ross ss46 Antarctica ’36 Sea ² S,, o64 V, ss 1972 Adélie 03 it ’29 has; ² 1979 W Land been, in), Palmer Archipelago ( Vervoort, 1972b), oV Peter I Island (Blanco and Bellusci de Miralles, 1972), oV Peterman Island, Low Island, 63ss22’/62ss00¾S, 61ss55¾W, Puerto Leith, oV Bryde Island, and Penónsula Sanavirón, 62ss40¾S, 64ss10¾W (Blanco, 1992). The Polarstern material comes from the east coast of the Weddell Sea (oV Riiser- Larsen Ice Shelf). It is also known oV Bouvet Island (Broch, 1948). Doubful records are those from Kerguélen (Millard, 1977) and 63ss40¾S, 64ss08¾W ( Vervoort, 1972a).